Light reflector unit for a photographic camera

ABSTRACT

A light reflector unit (12) for use with a photographic camera (10) for reflecting light from a light source (13), such as a flash gun, towards the subject to be photographed, the unit (12) comprising a hollow casing (15) having a window (16) for admitting light from the light source (13) into the casing (15), means (28) within the casing 15 for splitting the admitted light and for condensing the split light into separate beams of light, reflective surfaces (26) within the casing (15) for deflecting each beam of light to one of a plurality of windows (18) located such that when the reflector unit (12) is positioned on a camera (10) they face in the same direction as the lens of the lens unit (11) of the camera (10) and are disposed at discrete locations around the lens unit (11).

This invention relates to a light reflector unit for use with aphotographic camera for reflecting light from a light source towards asubject to be photographed. When using a camera with a conventionalflash gun mounted on top of the camera to take close-up photographs of asubject there are problems due to parallax and this produces unevenillumination of the subject.

In order to overcome the problems of parallax and to produce an evenillumination of the subject a "ring flash" unit is known which consistsof an annular flash tube which surrounds the lens unit of the camera.The disadvantages of a "ring-flash" unit are that it requires a powerpack which is remote from the flash unit, it is expensive to manufactureand because of the large flash tube it requires a large power pack. Alsothe "ring-flash" unit can not be used as a constant light source, i.e.,one that can be used to illuminate the subject before the photograph istaken in order to enable the photographer to view the illuminatedsubject before actuating the shutter of the camera.

The light reflector unit according to the present invention is one thathas the advantages of a "ring-flash" unit but which does not suffer fromthe disadvantages of a "ring-flash unit" and which can be used with aconventional flash gun and with a constant light source.

According to the present invention there is provided a light reflectorunit for use with a photographic camera for reflecting light from alight source towards a subject to be photographed, comprising a hollowcasing which can be positioned on a camera between the light source andthe lens unit of the camera, a window in the casing for admitting lightfrom a said light source into the casing, means within the casing forsplitting the admitted light, means for condensing at least some of theadmitted light into two or more beams of light, light reflectivesurfaces within the casing for deflecting each beam of light to one of aplurality of light emitting outlets located on the casing at a positionsuch that when said casing is positioned on a camera the outlets face inthe same direction as the lens of the lens unit and are disposed atdiscrete locations around the lens unit, or said light reflectivesurfaces deflect the beams to an annular outlet located on the casingsuch that it faces in the same direction as the lens of the lens unitand surrounds the lens unit, the or each outlet being provided with alens or a diffuser.

Some embodiments of the present invention will now be described, by wayof examples, with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic front view of a camera provided with a lightsource and a light reflector unit according to the present invention;

FIG. 2 is a side view of the camera and attachments shown in FIG. 1;

FIG. 3 is a diagrammatic front view of a camera provided with a lightsource, a light reflector unit according to the present invention, and alight reflector surrounding the lens;

FIG. 4 is a side view of the camera and attachments shown in FIG. 3;

FIG. 5 is an exploded view of the light reflector unit, showing thecomponent parts thereof;

FIG. 6 is an exploded view of the light splitting, condensing,reflective and spreading devices of the light reflector unit;

FIG. 7 is a diagrammatic perspective view of a camera provided with alight source, a reflector device according to the present invention andhinged deflectors and/or diffusers;

FIG. 8 is a diagrammatic perspective view of an embodiment of a lightreflector unit according to the present invention provided with afrusto-conical reflector;

FIG. 9 illustrates a bracket for providing physical and electricalconnection of a flash unit to the hot shoe of a camera;

FIGS. 10 and 11 show diagrammatically the flash gun and light reflectorunit in the two positions on the camera using a reversible bracket;

FIG. 12 is a diagrammatic exploded perspective view of the flash gun,light reflector unit and clip member for fastening the light reflectorunit to the flash gun;

FIG. 13 is a diagrammatic view showing the clip member fastening thelight reflector to the flash gun;

FIG. 14 shows perspective views of two camera lens which can be used inthe outlet windows of the light reflector unit;

FIG. 15 is a diagrammatic illustration showing the light paths from thellight reflector unit;

FIG. 16 shows diagrammatically a side elevation of a camera providedwith a light source and a light reflector unit according to the presentinvention and a multi-lens panel in front of the light reflector unit;

FIG. 17 is a perspective view of a suitable multi-lens panel;

FIG. 18 is a diagrammatic perspective view showing how the lightreflector unit can be carried by a filter holder on a camera, and

FIG. 19 shows a light diffuser carried by a filter holder on a camera.

FIGS. 1 and 2 show a camera 10 provided with a lens unit 11. Locatedabove the lens unit 11 is a light reflector unit 12 according to thepresent invention. Mounted on top of the light reflector unit 12 is aconventional flash gun 13 which has its light emitting face facing theupper side of the light reflector unit 12. The flash gun 13 can beconnected to the accessory shoe of the camera 10 as will be described ingreater detail hereafter.

FIGS. 3 and 4 show a frusto-conical reflector member 14 which partlysurrounds the lens unit 11.

The light reflector unit 12 comprises a hollow casing 15 formed ofsuitable light impervious material such as metal or plastics material.The upper wall of the casing 15 is provided with a window 16 which maybe open or closed by a transparent closure. The front wall 17 of thecasing 15 is provided with two windows 18.

On the inside of the casing 15 some of the surfaces are provided withlight reflective material, such as mirrored material, polished metalmaterial, etc.

A preferred embodiment of the light reflector unit 12 is shown in FIG.5. The casing 15 has end walls 19 which are forwardly inclined. Providedon the upper wall 20 of the casing 15 is a raised portion 21 in whichthe window 16 is provided, the ends of the raised portion being upwardlyand outwardly inclined to form a channel 22. The raised portion 21 isalso provided with undercut inwardly facing recesses 23 located in aplane beneath the window 16. The front of the casing 15 is open toreceive a unit 24 which comprises a hollow member having a front wall 25provided with the windows 18, inclined end walls 26 and a rear wall 27.The bottom wall of the unit 24 has two upwardly inclined surfaces 28which at their upper end terminate in a transverse opening 29 which isdivided into a plurality of openings by webs 30. The surfaces of theinclined end walls 26 and the inclined surfaces 28 are covered with alight reflective material. The inclined surfaces 28 and the opening 29form a light splitter.

The window 16 is covered by a diffuser 31 which engages the recesses 23.Each window 18 is closed by a lens 32 carried on a cover plate 33. Thecomponent parts of the unit 12 can be held together in any suitablemanner.

In use, the light emitted from the flash unit 13 passes into the window16. Some of the admitted light passes straight through the opening 29and is directed through a window (not shown) in the bottom of the casing15 and onto the frusto-conical surface of the reflector member 14 anddeflected towards the subject being photographed. The webs 30 serve toconfine the light passing through the opening 29 and prevent itspreading. When no reflector 14 is provided, such as in the arrangementshown in FIGS. 1 and 2, then the opening 29 can be blanked-off and thereis no window in the bottom wall of the casing. The remainder of theadmitted light is split into two paths, one path of light striking thesurface of one of the upwardly inclined surfaces 28 and the otherstriking the surface of the other upwardly inclined surface 28. Theinclined surfaces 28 condense the light into beams which are reflectedonto the respective interior surfaces of the inclined end walls 26 whichdeflect the beams of light to the windows 18 where they are diffused anddirected to the subject 37 to be photographed. Each of the windows 18may be provided with a prism or fresnel screen 34 as shown in FIG. 6 andwith a frosted screen 35. As will be seen from FIG. 6, the reflectormember 14 can be provided with or replaced by a reflector 36.

The upwardly inclined surfaces 28 may be curved or concave with theconcavity directed towards the interior of the unit 24. It will be seentherefore that the light reflector unit 13 splits up the light receivedfrom the flash gun 13 into three paths, two of these paths of lightbeing condensed into pencil beams which are directed to optimumpositions around the lens unit 11 of the camera 10, and at thesepositions deflected towards the subject 37 to be illuminated andphotographed. On leaving the beam splitter, the light is condensed andthe degree of condensation is selected to suit the particular design oflight reflector unit 12.

In the embodiment shown in FIG. 7 the light reflector unit 12 is eithernot provided with the opening 29 or the opening 29 is blanked-off andthe light received from the flash gun 13 is split and condensed into twobeams which are directed to the windows 18. Mounted on the end of thelens unit 11 is a diffuser 38. The diffuser 38 may consist of an annulardiffuser or as shown in FIG. 7 a plurality of deflectors and/ordiffusers 34 hinged to a mounting ring 40. Only two deflectors and/ordiffusers 39 will be used at any one time. This arrangement enables anylength of lens unit 11 to be fitted to the camera 10 without itobscuring the light directed towards the subject to be photographed. Therequired exposure can be calculated by meansuring the distance betweenthe diffuser 38 and the subject and not the flash to the subjectdistance via the beam splitter.

The light reflector unit 12 produces an even illumination of the subject37 at close range, i.e. 30 mm or less. Colour filters can be used withthe windows 18 of the unit 12 to give special effects. Each beam oflight may be controlled with lenses deflectors and/or light absorbingscreens to vary the lighting on the subject, i.e. to produce shadows onone side. Closeup frames may be used to surround the light reflectorunit 12 without any shadows of the frame appearing on the subject.

If the diffuser/deflector 38 shown in FIG. 7 is removed the twoconcentrated light beams from the unit 12 can be used to illuminate adistant subject.

The flash gun 13 can be detached from the unit 12 and can be used in aconventional manner.

FIG. 8 shows a reflector member 41 which is integral with the reflectorunit 12. The reflector member 41 will bounce back light reflected fromthe subject 37 and surroundings to give "fill-in" lighting.

In all the embodiments described the flash gun 13 can be replaced by aconstant light source, i.e. a tungsten light source. This enables thephotographer to see the effect of the lighting on the subject 37 beforeactuating the shutter of the camera 10. The flash gun 13 can be providedwith a light sensor 42.

FIG. 9 illustrates a mounting bracket 43 which can be attached to theconventional hot shoe of a camera 10 and used for holding a flash gun 13on the camera 10.

FIGS. 10 and 11 illustrate a reversible mounting bracket 43 which can beattached to the conventional hot shoe 44 of a camera 10 and used to holda conventional flash gun 13 in the desired position on the camera 10,i.e. with its light emitting face directed downwardly. The reversiblebracket 43 has a mounting flange 45 extending upwardly from one edge.When the bracket 43 is connected to the hot shoe 44 with the flange 45rearmost the reflector unit 12 which is connected to the flash gun 13will be close to the body of the camera 10 as shown in FIG. 10 and whenthe bracket 43 is connected to the hot shoe 44 with the flange 45forwardmost the reflector unit 12 will be located at or near the forwardend of the lens unit 11 of the camera 10 as shown in FIG. 11.

FIGS. 12 and 13 illustrate a mounting clip 46 which can be fastened tothe flash gun 13 by screws or by an adhesive and used for mounting thereflector unit 12 on the flash gun 13. The mounting clip 46 comprises aflat body portion 47 provided with an aperture 48 to allow light to passthrough it, and at each side the body portion 47 is provided with apivotable clamp member 49 which engages with the undercut or dovetailsection recess 22 provided on the top of the casing of the reflectorunit 12. The two clamp members 49 are caused to pivot by the applicationof manual force to disengage them from the recesses 22 in order todetach the unit 12 from the flash gun 13. The clamp members 49 can bespring loaded or simply be resilient.

FIG. 14 shows two different forms of lens which can be used in thewindows 18 of the unit 12. That shown at 50 is symmetrically concavewhilst that shown at 51 is assymetrically concave. The spread of lightfrom lens 50 will be symmetrical whilst that from lens 51 will have asideways deflection, as shown in FIG. 15.

FIG. 16 shows the end of the lens unit 11 provided with a multi-lenspanel 52. The panel 52 is shown in greater detail in FIG. 17, and thearcuate vertical surfaces 53 on one side and arcuate horizontal surfaces54 on its other side.

FIG. 18 shows diagrammatically a filter holder 55 provided on the end ofthe lens unit 11. The reflector unit 12 is provided with a mountingflange 56 having an arcuate portion which surrounds the lens of the unit11 and which is received in the holder 55. A reflector 57 which receiveslight from the unit 12 is provided with a mounting flange 58 whichsurrounds the lens of the unit 11 and which is received in the holder55.

In FIG. 19 the filter holder 55 carrier a diffuser 59 for diffusing thebeams of light emitted from the windows 18 of the reflector unit 12.

It will be appreciated that there may be more than two windows 18provided on the reflector unit 12 and these may be arcuate in frontelevation. It is also possible to provide an annular window from whichthe reflector light is directed towards the subject.

I claim:
 1. A light reflector unit for use with a photographic camerafor reflecting light from a light source towards a subject to bephotographed, said unit comprising a hollow casing which can bepositioned on a camera between a light source and the lens unit of thecamera, a window in the casing for admitting light from said lightsource into the casing, at least one light emitting outlet from thecasing, means for positioning the casing with said outlets facing thesame direction as the lens unit of said camera, means within the casingfor splitting the admitted light, means for condensing at least some ofthe admitted light into at least two beams of light, and lightreflective surfaces within the casing for reflecting each beam of lightto said light emitting outlet, said outlet being provided with a lens ora diffuser.
 2. A light reflector as set forth in claim 1 wherein saidoutlet is arcuate and is adapted to be positioned at least partiallysurrounding the lens unit of the camera.
 3. A light reflector as setforth in claim 1 including a plurality of said outlets adapted to bedisposed at discrete locations around the lens unit of a camera, saidlight reflective surfaces reflecting at least a portion of each beam oflight to one of said outlets.
 4. A light reflector unit as set forth inclaims 1, 2, or 3 in which the casing is provided with an opening whichdirects some light from said light source directly across the casingonto a reflector located beneath said casing.
 5. A light reflector unitas set forth in claims 1, 2, or 3 further including a diffuser for eachoutlet.
 6. A light reflector unit as set forth in claims 2 or 3 whereinthe casing includes a hollow casing member open at its forward face, anda unit which is received in the casing member mounting said means forsplitting the admitted light, said means for condensing the light intotwo or more beams, said light reflective surfaces and said lightemitting outlets.
 7. A light reflector unit as set forth in claim 6including a lens carried on a cover plate for each light emittingoutlet.
 8. A light reflector unit as set forth in claims 1, 2, or 3wherein said means for splitting the admitted light comprises twoupwardly extending light reflective surfaces inclined towards each otherat their upper ends.
 9. A light reflector unit as set forth in claims 1,2, or 3 wherein said means for positioning said casing includes meansfor attacing said unit to a light source.
 10. A light reflecting unit asset forth in claim 9 wherein said means for attaching comprises a platewhich can be secured to said light source, said plate includingpivotable clamp members each of which engages a recess provided on theupper wall of said casing.
 11. A light reflector unit as set forth inclaim 9 wherein said means for attaching includes a mounting flangeprovided on the casing and which can be fixed to a filter holderprovided on the lens unit of the camera.
 12. A light reflector unit asset forth in claims 1, 2, or 3, further including a frusto-conicaldeflector adapted to extend around the lens unit of a camera.